Evaluating ice-rafted debris as a proxy for glacier calving in Upernavik Isfjord, NW Greenland

Flor Vermassen, David J. Wangner, Laurence M. Dyke, Sabine Schmidt, Amalie E. Cordua, Kurt H. Kjær, Konstanze Haubner, Camilla S. Andresen

Research output: Contribution to journalArticleResearchpeer-review

11 Citations (Scopus)

Abstract

Records of ice-rafted debris (IRD) in sediments are commonly used as a proxy for iceberg production and to reconstruct past changes of glacier stability. However, the interpretation of IRD is complex as multiple processes modulate its variability. This study investigates the relationship between IRD variability and glaciological change by measuring IRD records from Upernavik Fjord and comparing these to frontal positions of Upernavik Isstrøm during the past century. Results show that the spatial variability of IRD deposition throughout the fjord is high, indicating that randomness inherent to IRD distorts the calving signal. However, we investigate whether IRD records can be combined to improve the reconstruction, as previously suggested, and show the importance of core site selection and number of cores on this approach. The outer-fjord core compares relatively well to the observed front positions and this is reflected in the composite record: increased IRD deposition in 1937–1946, 1968–1980, and 1996–1999 occurred during periods of faster retreat. Comparison with climatic records shows that the calving episodes in the late ‘30 s/early ‘40 s and late ‘90 s are related to warm ocean and air temperatures, whereas intensified retreat and calving during the ‘70 s reflects partly an internal glacier response to the fjord geometry.

Original languageEnglish
Pages (from-to)258-267
Number of pages10
JournalJournal of Quaternary Science
Volume34
Issue number3
DOIs
Publication statusPublished - Apr 2019

Keywords

  • glacier retreat
  • ice-rafted debris
  • proxy evaluation
  • Upernavik Isfjord
  • Upernavik Isstrøm

Programme Area

  • Programme Area 5: Nature and Climate

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